package com.bangcommunity.bbframe.sdm.utils;

import com.bangcommunity.bbframe.common.utils.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.util.Collection;
import java.util.Map;

/**
 * User: joeytang Date: 2012-06-05 02:11 实现获取Request/Response/Session与绕过jsp/freemaker直接输出文本的简化函数.
 */
public class RenderUtils {
    /**
     * Logger for this class
     */
    private static final Log logger = LogFactory.getLog(RenderUtils.class);

    // header 常量定义
    private static final String ENCODING_PREFIX = "encoding";
    private static final String NOCACHE_PREFIX = "no-cache";
    private static final String ENCODING_DEFAULT = "UTF-8";
    private static final boolean NOCACHE_DEFAULT = true;

    // 取得Request/Response/Session的简化函数 //

    // 绕过jsp/freemaker直接输出文本的函数 //

    /**
     * 直接输出内容的简便函数.
     *
     * eg. render("text/plain", "hello", "encoding:GBK"); render("text/plain", "hello",
     * "no-cache:false"); render("text/plain", "hello", "encoding:GBK", "no-cache:false");
     *
     * @param headers
     *            可变的header数组，目前接受的值为"encoding:"或"no-cache:",默认值分别为UTF-8和true.
     */
    public static void render(HttpServletResponse response, final String contentType, final String content,
            final String... headers) {
        try {
            // 分析headers参数
            String encoding = ENCODING_DEFAULT;
            boolean noCache = NOCACHE_DEFAULT;
            for (String header : headers) {
                String headerName = StringUtils.substringBefore(header, ":");
                String headerValue = StringUtils.substringAfter(header, ":");

                if (StringUtils.equalsIgnoreCase(headerName, ENCODING_PREFIX)) {
                    encoding = headerValue;
                } else if (StringUtils.equalsIgnoreCase(headerName, NOCACHE_PREFIX)) {
                    noCache = Boolean.parseBoolean(headerValue);
                } else
                    throw new IllegalArgumentException(headerName + "不是一个合法的header类型");
            }
            // 设置headers参数
            String fullContentType = contentType + ";charset=" + encoding;
            response.setContentType(fullContentType);
            if (noCache) {
                response.setHeader("Pragma", "No-cache");
                response.setHeader("Cache-Control", "no-cache");
                response.setDateHeader("Expires", 0);
            }
            PrintWriter writer = response.getWriter();
            writer.write(content);
            writer.flush();
            writer.close();
        } catch (Exception e) {
            logger.error("render exception", e);
        }
    }

    /**
     * 直接输出文本.
     */
    public static void renderText(HttpServletResponse response, final String text, final String... headers) {
        render(response, "text/plain", text, headers);
    }

    /**
     * 直接输出Error文本.
     */
    public static void renderError(HttpServletResponse response, final String text, final String... headers) {
        render(response, "text/plain", "{'error':'" + text + "'}", headers);
    }

    /**
     * 直接输出HTML.
     */
    public static void renderHtml(HttpServletResponse response, final String html, final String... headers) {
        render(response, "text/html", html, headers);
    }

    /**
     * 直接输出XML.
     */
    public static void renderXml(HttpServletResponse response, final String xml, final String... headers) {
        render(response, "text/xml", xml, headers);
    }

    /**
     * 直接输出JSON.
     *
     * @param string
     *            json字符串.
     */
    public static void renderJson(HttpServletResponse response, final String string, final String... headers) {
        render(response, "application/json", string, headers);
    }

    /**
     * 直接输出JSON.
     *
     * @param map
     *            Map对象,将被转化为json字符串.
     */
    @SuppressWarnings("rawtypes")
    public static void renderJson(HttpServletResponse response, final Map map, final String... headers) {
        String jsonString = null;
        if (null != map) {
            jsonString = JsonMapper.getInstance().toJson(map);
        }
        renderJson(response, jsonString, headers);
    }

    /**
     * 直接输出JSON.
     *
     * @param object
     *            Java对象,将被转化为json字符串.
     */
    public static void renderJson(HttpServletResponse response, final Object object, final String... headers) {
        String jsonString = null;
        if (null != object) {
            if (object instanceof Collection) {
                jsonString = JsonMapper.getInstance().toJson(object);
            } else {
                jsonString = JsonMapper.getInstance().toJson(object);
            }
        }
        renderJson(response, jsonString, headers);
    }

}
